states of matter

• kinetic particle theory of matter: a model that describes the arrangement, movement and energy of particles in a substance
• properties of solids:

  • particles close together
  • regular, fixed arrangement
  • particles vibrate around a fixed position
  • low kinetic energy
  • have fixed volume and shape
  • cannot flow
  • cannot be compressed
• properties of liquids:

  • particles are touching
  • randomly arranged
  • move over & around each other
  • medium kinetic energy
  • have fixed volume
  • no fixed shape
  • flows and takes shape of container its in
  • not easily compressed as limited space
• properties of gases:

  • particles far apart
  • randomly arranged
  • move quickly in all directions
  • high kinetic energy
  • no fixed shape or volume
  • can flow
  • fills a container its in
  • can be compressed as particles have space between them
• solid -> liquid = melting
• liquid -> gas = evaporating/boiling
• gas -> liquid = condensing
• liquid -> solid = freezing
• solid -> gas = sublimation
• gas -> solid = deposition
• physical change: a change where no new substances are formed as the particles have different strengths of forces between them.

  changes of state are physical changes because their forces of attraction are overcome by kinetic energy
• chemical change: an irreversible chemical reaction involving the rearrangement of atoms of one or more substances resulting in the formation of at least one new substance (bonds between atoms are broken and new bonds are formed)
• when melting/evaporating/boiling:

  • energy is transferred to the substance through heating
  • the thermal energy gained by the particles is converted to kinetic energy
  • as particles gain energy, forces of attraction between them are overcome
  • they begin to move more, changing state
• when condensing/freezing:

  • energy is transferred from the substance to the environment
  • thermal energy is released
  • particles have less kinetic energy
  • forces of attraction form between the particles
  • particles move less as they become more attracted to each other
• predicting a substance’s physical state:

  • if given temperature < melting point then state is solid
  • is given temperature > melting point but < boiling point then state is liquid
  • if given temperature is > boiling point then state is gas